Fabrication of silicon carbide nanoceramics

1996 ◽  
Vol 11 (7) ◽  
pp. 1601-1604 ◽  
Author(s):  
Mamoru Mitomo ◽  
Young-Wook Kim ◽  
Hideki Hirotsuru
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Average Particle Size ◽  
Liquid Phase Sintering ◽  
Carbide Powder ◽  
Average Particle ◽  
Average Grain Size ◽  
Silicon Carbide Powder

Ultrafine silicon carbide powder with an average particle size of 90 nm was densified by hot-processing with the addition of Al2O3, Y2O3, and CaO at 1750 °C. Silicon carbide nanoceramics with an average grain size of 110 nm were prepared by liquid phase sintering at low temperature. The materials showed superplastic deformation at a strain rate of 5.0 × 10-4/s at 1700 °C, which is the lowest temperature published. The microstructure and deformation behavior of materials from a submicrometer powder were also investigated as a reference.

scholarly journals Effect of Particle Size on Microstructure and Element Diffusion at the Interface of Tungsten Carbide/High Strength Steel Composites

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4164 ◽  
Author(s):  
Hongmei Zhang ◽  
Hongnan Li ◽  
Ling Yan ◽  
Chao Wang ◽  
Fangfang Ai ◽  
...  
Keyword(s):  
Particle Size ◽  
Tungsten Carbide ◽  
High Strength Steel ◽  
Average Particle Size ◽  
High Strength ◽  
Average Particle ◽  
Micro Hardness ◽  
Vacuum Sintering ◽  
Element Diffusion ◽  
Average Grain Size

The microstructure and micro-hardness of tungsten carbide/high strength steel (WC/HSS) composites with different particle sizes were analyzed by optical microscopy (OM), scanning electron microscopy (SEM), ultra-high temperature laser confocal microscopy (UTLCM) and micro-hardness testing. The composites were prepared by cold pressing and vacuum sintering. The results show that WC density tends to increase as the average grain size of WC decreases and the micro-hardness of WC increases with the decrease of WC particle size. The micro-hardness of WC near the bonding interface is higher than that in other regions. When the particle size of WC powder particles is 200 nm, a transition layer with a certain width is formed at the interface between WC and HSS, and the combination between the two materials is metallurgical. The iron element in the HSS matrix diffuses into the WC structure in contact with it, resulting in a fusion layer of a certain width, and the composite interface is relatively well bonded. When the average particle size of WC powder is 200 nm, W, Fe and Co elements significantly diffuse in the transition zone at the interface. With the increase of WC particle size, the trend of element diffusion decreases.

scholarly journals Study on the Shear Band of Sand with Various Particle Characteristics Using PIV Analysis

2019 ◽  
Vol 92 ◽  
pp. 06005
Author(s):  
Shintaro Kajiyama ◽  
Yukio Nakata ◽  
Ryota Miyamoto ◽  
Masato Taue
Keyword(s):  
Particle Size ◽  
Shear Band ◽  
Inclination Angle ◽  
Average Particle Size ◽  
Average Particle ◽  
Sample Standard Deviation ◽  
Particle Characteristics ◽  
Coral Sand ◽  
Average Grain Size ◽  
Toyoura Sand

The phenomenon of ground undergoing large plastic deformation, leading to collapse, occurs due to the localization of unstable deformation. The investigation of shear band is important in order to understand the destructive phenomenon. Therefore, a series of experiments were conducted on sands with different particle characteristics so that behaviour of the shear band of sand under plane strain compression could be investigated. Specifically, Toyoura sand and two kinds of coral sand, hereafter referred to as coral sand A (with smaller average particle size) and coral sand B (with larger average particle size) were used. The shear band was evaluated using PIV (Partial Image Velocimetry) analysis. As a result, it became clear that the relationship between shear inclination angle and internal friction angle does not hold for the two kinds of coral sand because the shear inclination angle is low. The ratio of the average value of the shear band width to the average grain size at the peak was 10 to 20 times, 7 to 10 times, and 5 to 8 times in the order of Toyoura sand, coral sand A, and coral sand B. The sample standard deviation was 0.1 to 0.9 mm, 0.9 to 1.6 mm, and 1.4 to 1.9 mm.

Study on the Microstructure and Properties of ZL205A Alloy under Partial Remelting Treatment

2012 ◽  
Vol 538-541 ◽  
pp. 1183-1186
Author(s):  
Min Li ◽  
Lan Rong Cai ◽  
Peng Xin Liu
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Tensile Strength ◽  
Average Particle Size ◽  
Average Particle ◽  
High Tensile Strength ◽  
Microstructure And Properties ◽  
Partial Remelting ◽  
Average Grain Size ◽  
Zl205a Alloy

In this paper, effects of partial remelting treatment on microstructure and properties of ZL205A alloy were studied in detail. The results show that the grain size of ZL205A alloy decreases at different degree. The grain size increases first and then decreases with increasing of returns content. The average grain size of the primary ZL205A alloy was measured to be about 60 μm, and the good result can be got of the ZL205A alloys with the average particle size of α (Al) phase being about 33 μm after adding 20wt.% returns. The ZL205A alloy with 20 wt.% returns has a considerably high tensile strength and yield strength of 525MPa and 445 MPa, respectively, which is much higher than 501 MPa and 421 MPa of primary ZL205A alloy, meanwhile the elongation level is up to14%.

scholarly journals Research on the Influence of the Manufacturing Process Conditions of Iron Sintered with the Addition of Layered Lubricating Materials on its Selected Properties

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4782
Author(s):  
Wieslaw Urbaniak ◽  
Tomasz Majewski ◽  
Ryszard Wozniak ◽  
Judyta Sienkiewicz ◽  
Jozef Kubik ◽  
...  
Keyword(s):  
Particle Size ◽  
Boron Nitride ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Hexagonal Boron Nitride ◽  
Average Particle Size ◽  
Layered Materials ◽  
Process Conditions ◽  
Average Particle ◽  
Average Grain Size

The purpose of the conducted experiments was to test the selected properties of materials intended for porous sintered bearings containing layered materials in the form of powders with an average particle size of 0.5–1.5 μm, with very good tribological properties. The subject of the research was a sinter based on iron powder with the addition of layered materials; molybdenum disulfide MoS2 (average particle size 1.5 μm), tungsten disulfide WS2 (average particle size 0.6 μm), hexagonal boron nitride, h-BN (average particle size 0.5 and 1.5 μm) with two different porosities. The article presents the results of density and porosity tests, compressive strength, metallographic and tribological tests and the assessment of changes in the surface condition occurring during the long storage period. The use of layered additives allows for an approximately 20% lower coefficient of friction. In the case of sulfides, the technological process of pressing 250 MPa, 350 MPa, and sintering at a temperature of 1120 °C allows us to obtain a material with good strength and tribological properties, better than in the case of h-BN. However, the main problem is the appearance of elements from the decomposition of sulfide compounds in the material matrix, which results in rapid material degradation. In hexagonal boron nitride, such disintegration under these conditions does not occur; the material as observed does not degrade. In this case, the material is characterized by lower hardness, resulting from a different behavior of hexagonal boron nitride in the pressing and sintering process; in this case, pressing at a pressure of 350 MPa seems to be too low. However, taking into account that even with these technological parameters, the obtained material containing 2.5% h-BN with an average grain size of 1.5 μm allowed obtaining a coefficient of friction at the level of 0.41, which, with very good material durability, seems to be very positive news before further tests.

Fabrication of Bioactive Apatite Nuclei-Precipitated Titanium Alloys by Using Sandblasting

2012 ◽  
Vol 529-530 ◽  
pp. 553-558 ◽  
Author(s):  
Hiroshi Mizuno ◽  
Takeshi Yabutsuka ◽  
Takeshi Yao
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Average Particle Size ◽  
Average Particle ◽  
Mechanical Interlocking ◽  
Alloy Plate ◽  
Ti Alloys ◽  
Silicon Carbide Particles ◽  
Carbide Particles ◽  
High Adhesive Strength

Micropores were formed on the surface of Ti metal, Ti-15Mo-5Zr-3Al alloy, Ti-12Ta-9Nb-3V-6Zr-O alloy plate by doubled sandblasting process using silicon carbide particles with 14.0 μm for average particle size as first process, then using the particles with 3.0 μm for average particle size as second process. Apatite Nuclei (AN) were precipitated in the pores. By these treatments, bioactive AN-precipitated Ti alloys were fabricated. Bioactivity of the AN-precipitated Ti alloys was examined by soaking in SBF and it was observed that hydroxyapatite was induced on the surface of the Ti alloys within 1 d. High adhesive strength of hydroxyapatite layer was achieved due to a mechanical interlocking effect between hydroxyapatite formed in the micropores and the plate.

Fabrication of Bioactive Apatite Nuclei Precipitated Ti-15Mo-5Zr-3Al Alloy by Using Doubled Sandblasting Process

2014 ◽  
Vol 631 ◽  
pp. 231-235 ◽  
Author(s):  
Takeshi Yabutsuka ◽  
Hiroshi Mizuno ◽  
Ryoki Karashima ◽  
Takeshi Yao
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Adhesive Strength ◽  
Average Particle Size ◽  
Average Particle ◽  
Alloy Plate ◽  
Ti Alloys ◽  
Size Of Particles ◽  
Silicon Carbide Particles ◽  
Carbide Particles

Micropores were formed on the surface of Ti-15Mo-5Zr-3Al alloy plate by doubled sandblasting process using silicon carbide particles with 14.0 μm and/or 3.0 µm average particle size by changing the combination of the size of particles. Apatite Nucleus (AN) was precipitated in the pores. By these treatments, bioactive AN precipitated Ti alloys were fabricated. Bioactivity of the Ti alloys was examined by soaking in SBF. Formed hydroxyapatite showed highest adhesive strength in the case of sandblasting using 14.0 μm particles then using 3.0 μm particles.

scholarly journals Studying the Crystal Structure, Topography, and Anti-bacterial of a Novel Titania (TiO2 NPs) Prepared by a Sol-gel Manner

2019 ◽  
Vol 16 (4) ◽  
pp. 0910
Author(s):  
Fayyadh Et al.
Keyword(s):  
Particle Size ◽  
Antibacterial Activity ◽  
Titanium Dioxide ◽  
Calcination Temperature ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Particle ◽  
Gram Negative ◽  
Tio2 Nps ◽  
Average Grain Size

In this research, titanium dioxide nanoparticles (TiO2 NPs) were prepared through the sol-gel process at an acidic medium (pH3).TiO2 nanoparticles were prepared from titanium trichloride (TiCl3) as a precursor with Ammonium hydroxide (NH4OH) with 1:3 ratio at 50 °C. The resulting gel was dried at 70 °C to obtain the Nanocrystalline powder. The powder from the drying process was treated thermally at temperatures 500 °C and 700 °C. The crystalline structure, surface morphology, and particle size were studied by using X-ray diffraction (XRD), Atomic Force Microscopy (AFM), and Scanning Electron Microscope (SEM). The results showed (anatase) phase of titanium dioxide with the average grain size of 110 nm at 500 °C calcination temperature, and (anatase- rutile) mixed phase of titanium dioxide with the average particle size of 118.1 nm at 700 °C calcination temperature. The anti-bacterial activity of the synthesis specimens was recorded through the Kirby-Bauer disc method (disc devotion method). The results displayed a pretty excellent antibacterial activity of TiO2 NPs to bacteria strains: Gram positive staphylococcus aureus, gram negative pseudomonas aeruginosa, and "gram negative escherichia coli. The sensitivity of the tested bacteria to TiO2 NPs depends on the oxidation state of the TiO2 NPs, particle size, volume, and the density of the unit cell. The small- average particle size of titanium dioxide particles showed high antibacterial activity against bacteria, while the larger- average particle size of titanium dioxide particles showed less antibacterial activity. The novelty of this production is the manufacturing of a novel kind of TiO2 NPs and achievement its best antibacterial activity.

Recovery of Silicon and Silicon Carbide Powder from Waste Silicon Wafer Sludge

2013 ◽  
Vol 761 ◽  
pp. 65-68 ◽  
Author(s):  
Woo Teck Kwon ◽  
Soo Ryong Kim ◽  
Y. Kim ◽  
Jee Ban Poudel ◽  
Sea Cheon Oh
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Linear Equation ◽  
Silicon Wafer ◽  
Point Of View ◽  
Carbide Powder ◽  
Drying Rate ◽  
Economic Point ◽  
Particle Size Analyzer ◽  
Silicon Carbide Powder

In an environmental and economic point of view, recycling of silicon wafer sludge is important. The aim of this work is to investigate the recycling method of silicon wafer sludge. Therefore, drying rate of silicon wafer sludge has been studied for separation of liquid and solid from sludge. Silicon and silicon carbide powder obtained from silicon wafer sludge were analyzed by SEM, XFR, XRD and particle size analyzer. The recovered oil was also characterized using GC-MS. From this work, it can be seen that the falling drying rate of silicon wafer sludge is linear equation. Various metal components have been found in recovered solid powder caused by wire sawing processing.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

2020 ◽  
Vol 27 (22) ◽  
pp. 3623-3656 ◽  
Author(s):  
Bruno Fonseca-Santos ◽  
Patrícia Bento Silva ◽  
Roberta Balansin Rigon ◽  
Mariana Rillo Sato ◽  
Marlus Chorilli
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Drug Loading ◽  
Average Particle Size ◽  
Delivery Systems ◽  
Average Particle ◽  
Minor Importance ◽  
Routes Of Administration ◽  
Non Invasive

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

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